The present invention relates to a powder inhaler, a blister pack and a method of dispensing powder. More particularly, it relates to a means and method by which a patient may inhale a variable dose of medicament.
It is known that powder containing a medicament may be inhaled for the treatment of certain conditions, such as asthma. Various systems have been proposed for storing and administering the powder.
U.S. Pat. No. 5,469,843 discloses a system in which a tape is coated with the powder and a sprung hammer strikes the back of the tape to release the powder. WO 94/12230 discloses a device in which an elongate blister pack is successively advanced through the device and in which means are provided for opening a blister and releasing a dose of powder. EP-A-0237507 discloses a device having a bulk powder reservoir from which doses of powder are successively transferred into an inhalation channel.
These various systems all have their own particular advantages and disadvantages, but these will not be considered here.
A disadvantage in common with all of these previous systems is that, within each type of system, it is necessary to provide a wide selection of different inhalers catering for users with different needs and for medicaments requiring different doses.
According to the present invention, there is provided a dry powder inhaler for use with a blister pack having a plurality of blisters, each blister containing a predetermined quantity of powder, the inhaler comprising:
an inhalation path; and
dosing means for opening the blisters and releasing the powder into the inhalation path for inhalation by the user, wherein
the dosing means comprises opening means suitable for simultaneously opening a predetermined plurality of said blisters such that, for each use of the inhaler, the actual dose administered is determined by the number of previously unopened blisters which are opened by the opening means.
The dosing means may comprise a control means for controlling the opening means to open a desired number of the blisters. Alternatively, for each use of the inhaler, the opening means may operate to open all of the predetermined plurality of blisters, the blister pack being positioned in the dosing means according to the required dose, such that the actual dose administered is determined by the number of unopened blisters on which the opening means operates.
In conjunction with this inhaler, the present invention also provides a blister pack comprising a plurality of blisters, each containing a predetermined quantity of powder for inhalation wherein each blister contains less than the clinical effective dose of said powder according to the particular one or more substances contained in the powder.
Thus, according to the present invention there is also provided a method of dispensing powder from a blister pack having a plurality of blisters, each blister containing a predetermined quantity of powder, the method comprising:
opening blisters of the blister pack so as to release the powder contained in said blisters into a delivery channel; and
choosing the number of blisters to be opened so as to provide the powder from said number of blisters in the delivery channel at the same time, the number being determined according to the quantity of powder required to be released into the delivery channel.
The present invention gives rise to many advantages.
Previously, for any one particular medicament, it was necessary to produce a selection of blister packs having respective blisters containing different doses. For instance, one blister pack would be produced having blisters containing the powder dose for an adult and another blister pack would be produced having blisters containing the powder dose for children. Clearly, the need to produce different types of blister pack adds to their cost of production. The present invention allows a single type of blister pack to be used for users with different needs. For instance, for the example given above, a child could use a dose of three blisters whereas an adult could use a dose of five blisters.
Similarly, while previous inhalers require a user to inhale two or more separate doses to receive an extra large dose, the present invention allows the dosage to be varied with a single inhalation.
Another advantage is that only one design of inhaler need be constructed to cater for a variety of blister packs respectively containing many different types of medicament Any variations required in the dosing between the various different types of medicament may be easily accomplished by the inhaler, which will merely open the required number of blisters.
The present invention allows additional flexibility which has not before been contemplated. In particular, the size of a dose can be varied for each inhalation. This is important for some patients, since their need of medicament can vary, for instance according to the time of day, their body activity or their food intake. In this respect, the present invention is particularly useful in conjunction with antidiabetic substances, such as insulin.
Indeed, according to the present invention, there is also provided a blister pack comprising a plurality of blisters, each containing a predetermined quantity of medicament for inhalation wherein the medicament comprises an antidiabetic medicament.
Medicaments suitable for use with the present invention are any which may be delivered by inhalation. Suitable inhalable medicaments may include for example xcex22-adrenoreceptor agonists for example salbutamol, terbutaline, rimiterol, fenoterol, reproterol, adrenaline, dpirbuterol, isoprenaline, orciprenaline, bitolterol, salmeterol, formoterol, clenbuterol, procaterol, broxaterol, picumeterol, TA-2005, mabuterol and the like, and their pharmacologically acceptable esters and salts; anticholinergic bronchodilators for example ipratropium bromide and the like; glucocorticosteroids for example beclomethasone, fluticasone, budesonide, tipredane, dexamethasone, betamethasone, fluocinolone, triamcinolone acetonide, mometasone, and the like, and their pharmacologically acceptable esters and salts; anti-allergic medicaments for example sodium cromoglycate and nedocromil sodium; expectorants; mucolytics; antihistamines; cyclooxygenase inhibitors; leukotriene synthesis inhibitors; leukotriene antagonists, phospholipase-A2 (PLA2) inhibitors, platelet aggregating factor (PAF) antagonists and prophylactics of asthma; antiarrhythmic medicaments, tranquilisers, cardiac glycosides, hormones, antihypertensive medicaments, antidiabetic-, such as insulin, antiparasitic- and anticancer-medicarnents, sedatives and analgesic medicaments, antibiotics, antirheumatic medicaments, immunotherapies, antifungal and antihypotension medicaments, vaccines, antiviral medicaments, proteins, polypeptides and peptides for example peptide hormones and growth factors, polypeptides vaccines, enzymes, endorphines, lipoproteins and polypeptides involved in the blood coagulation cascade, vitamins and others, for example cell surface receptor blockers, antioxidants, free radical scavengers and organic salts of N,Nxe2x80x2-diacetylcystine.
The present invention will be more clearly understood from the following description, given by way of example only, with reference to the accompanying drawings.